His predecessor had just been arrested in one of the most sweeping corruption scandals in Maryland history. Prince George's had a reputation of "pay-to-play" politics in which contractors were expected to grease palms to do business with the county. Some companies were wary of doing business there at all.

Now, even as he tries to repair the image of Maryland's second-most-populous county, Baker is playing a high-profile role in Annapolis on key issues before the General Assembly.

Last week, he changed the debate on gambling by declaring that he wants a billion-dollar, waterfront casino in Prince George's, complete with table games. He's in the thick of the fight to block the governor's plan to shift $239 million in teacher pension costs to local governments next year.

And Baker, a Democrat, could play a pivotal role on gasoline taxes and the rules for local contributions to schools, among other issues. Virtually every item on Gov. Martin O'Malley's ambitious 2012 agenda needs the votes of the solidly Democratic Prince George's delegation to have a shot at passage.

Baker, 53, is well qualified to influence those votes. He served two terms in the House of Delegates between 1995 and 2003 and is widely respected in Annapolis. He has forged a reputation for working closely with the county's legislative delegation, which, with 31 members, is among the largest.

"If we band together with our huge delegation down here, we'll have a powerful impact," Baker says.

Few local jurisdictions have more at stake this session. After decades of disappointment, the county has an agreement with the state that would transform its troubled, publicly owned hospital into a medical institution to rival those in Baltimore.

To finance that deal, some key legislators have said, the county might have to accept an expansion of slot machine gambling into Prince George's — an incursion that county officials have resisted under pressure from influential churches.

Senate President Thomas V. Mike Miller, who represents part of Prince George's, has said he sees no way to raise the county's share of the $600 million hospital project without revenue from a casino that would be established at either Rosecroft Raceway or National Harbor. Any decision to allow another slots casino in Maryland could be coupled with a statewide expansion in the types of games allowed.

Baker pushed back against that pressure last week. He said his administration would welcome a Las Vegas-style luxury casino near the Woodrow Wilson Bridge at National Harbor but rejected the idea of gambling at Rosecroft. He forcefully rejected any linkage between the hospital deal and approval of a casino in the county.

"The reason I'm asking the legislature to support this is not because of the hospital. We're going to get the money for the hospital," Baker said Friday.

Days after Baker's election in November 2010, lame duck County Executive Jack B. Johnson was arrested by the FBI on corruption charges. Much of the state heard the government's tapes of his frantic telephoned instructions to his wife to destroy a bribe check and to hide cash in her undergarments as authorities closed in.

In December, Johnson was sentenced to more than seven years in federal prison after admitting to crooked deals to cash in on the powers of his office. Even a position on the county hospital's medical staff was for sale, prosecutors said.

"It's a black eye on the county, and we're trying to move on," said Sen. Victor Ramirez, a Prince George's Democrat.

Baker, during his first year in office, focused on putting his stamp on a county government embedded with Johnson holdovers. This year, with his position better established, he's been almost as visible in Annapolis as in Upper Marlboro.

The hospital issue is a huge deal for Prince George's, perhaps as important as the governance of city schools was to Baltimore in the 1990s. County executives have been trying for decades to come up with a plan to shore up financing and improve the level of care at Prince George's Hospital Center.

Last year, Baker and O'Malley agreed on a plan under which the old hospital would be replaced by a better-situated institution run by the University of Maryland Medical System, but the agreement did not identify a revenue source. For some, gambling seems the obvious solution. Miller said Friday that he is sticking by his position that Rosecroft should be considered and that the issues of gambling and the hospital are inextricably linked.

Baker has taken a strong stance against O'Malley's proposal to shift part of the cost of teacher pensions to the counties where they are employed. He's urging lawmakers to oppose the proposal but to leave themselves an escape hatch in case a deal can be struck to defray the counties' costs.

The General Assembly also faces a likely donnybrook over transportation spending, including an O'Malley proposal to apply the 6 percent sales tax to gasoline. House Speaker Michael E. Busch says there isn't much chance for a transportation revenue bill unless it receives solid support from lawmakers in Prince George's, Montgomery County and Baltimore.

Baker said he'll urge county lawmakers to cast a "tough vote" on gas taxes but only if he's assured that part of the money will be directed toward county transit priorities such as the $1.9 billion Purple Line, a proposed light rail line between Prince George's and Montgomery counties.

"If we're going to bring the votes to the table, the money has to flow back to the ones making the sacrifices," Baker said. "If the numbers work out for us, we can deliver."

If dealing with a $120 million local budget shortfall, demands from the Senate president for a new casino and the hospital deal weren't enough, Prince George's residents are also looking to Baker to restore the image of a county that was burdened by corruption and feelings of disrespect even before Johnson's arrest.